U.S. Pat. No. 4,543,308 describes the measurement of luminescence intensities in exposed and processed photographic film by means of a commercial emission spectrometer, utilizing monochromators on both the illumination and detection sides of the instrument.
EP-A-0 610 994 which corresponds to U.S. Pat. No. 5,350,650 (incorporated herein by reference) describes a color photographic system which uses a color photographic system in which fluorescent interlayers are positioned between red-, green- and blue-sensitized recording layer units (without any dye image-forming materials) which form silver images of substantially the same hue. The color records are read out by scanning both the fluorescent and transmission records. The image densities are read from the two fluorescent interlayers by scanning through red and green filters, and the transmission density being scanned separately.
It is well understood that fluorescent or luminescent layers need to be excited at a particular wavelength to stimulate the production of radiation at another wavelength. A scanning process using a densitometer, with an absorption filter placed in the illuminating light path for fluorescent readout, is disclosed therein.
European Patent Application Number 95 202 482.6, now EP 0 702 483 A2 describes an apparatus and method for reading color records in a photographic material having silver images of substantially the same hue but representing exposures in at least three regions of the visible spectrum arranged in image layers, the material having at least one fluorescent or luminescent layer between two of the image layers. An improved scanner readout is provided, using mutually exclusive dichroic filters, for excitation of the fluorescent or luminescent layer and reading of radiation reflected therefrom.
U.S. Pat. No. 4,884,890 describes an optical system in which an image photosensor is positioned at the focal plane of the system for determining very narrow line width measurements of images having varying intensities, such as, fluorescing photoresist coated lines. The system includes a microscope arrangement for focusing excitation radiation, which is filtered by a blue filter and reflected by a dichroic beam splitter, onto the surface of a specimen having a photoresist pattern formed thereon. The pattern is enlarged and transmitted through the dichroic beam splitter and focused onto an eyepiece of the microscope arrangement. The dichroic beam splitter reflects radiation in the blue range and transmits radiation in the red range.